A Miniaturized Microstrip Resonant Unit Low-Pass Filter with Ultra-Wide Stop Band

Abstract

The invention provides an ultra-wide stopband miniaturized microstrip resonant cell low pass filter, which comprises a symmetrical resonant unit (1) and an asymmetrical resonant unit (2), wherein each of the two resonant units comprises high-impedance narrow wires (3), non-uniform open circuit short cutting wires (4) and a gap capacitor (5); four sections of high-impedance narrow wires (3) in the symmetrical resonant unit (1) are connected through a crossed point; each of the upper and lower high-impedance narrow wires (3) is connected with one non-uniform open circuit short cutting wire (4); the gap capacitors (5) are arranged between the left and right high-impedance narrow wires (3) and the non-uniform open circuit short cutting wires (4); three sections of high-impedance narrow wires (3) in the asymmetrical resonant unit (2) are connected through the T-shaped joints; one section of high-impedance narrow wire (3) is used for connecting the non-uniform open circuit short cutting wire (4); the gap capacitor (5) is arranged between the high-impedance narrow wire (3) and the nonuniform open circuit short cutting wire (4).

Description

technical field [0001] The invention belongs to the field of radio frequency and microwave filter design, in particular to an ultra-wide stop band miniaturized microstrip resonant unit low-pass filter. Background technique [0002] Microwave filter is a frequency control circuit that provides signal transmission in a certain frequency range and suppresses signals in other frequency bands. It is an indispensable part of radar systems, communication systems, measurement systems and other fields. The ideal filter is a two-port network, which should have frequency selective characteristics: that is, the signal can be transmitted without attenuation in the passband, and the signal cannot be transmitted at all in the stopband. According to the relative positions of passband and stopband, microwave filters can be divided into four basic types: low-pass, high-pass, band-pass and band-stop. Among them, the low-pass filter is an electronic filtering device that allows signals below t...

AI Technical Summary

Problems solved by technology

However, the transition between the passband and stopband of this structure is not steep enough to provide a wider stopband, and the parasitic passband is closer. If you want to get a steeper cutoff frequency, you need to increase the order, which will bring On the other hand, it will make the circuit size too large, which is not suitable for the case where the volume is required, which limits its application

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